WebSockets

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您可以将 WebSockets 用于与服务器的全部或部分通信，客户端配置方法请参阅 wsLink。

技巧

本文档重点说明 WebSockets 的特定使用细节。关于订阅的常规用法，请参见 订阅指南。

创建 WebSocket 服务器

bash
yarn add ws

bash
yarn add ws

server/wsServer.ts
ts
import { applyWSSHandler } from '@trpc/server/adapters/ws';
import { WebSocketServer } from 'ws';
import { appRouter } from './routers/app';
import { createContext } from './trpc';
 
const wss = new WebSocketServer({
  port: 3001,
});
const handler = applyWSSHandler({
  wss,
  router: appRouter,
  createContext,
  // Enable heartbeat messages to keep connection open (disabled by default)
  keepAlive: {
    enabled: true,
    // server ping message interval in milliseconds
    pingMs: 30000,
    // connection is terminated if pong message is not received in this many milliseconds
    pongWaitMs: 5000,
  },
});
 
wss.on('connection', (ws) => {
  console.log(`++ Connection (${wss.clients.size})`);
  ws.once('close', () => {
    console.log(`-- Connection (${wss.clients.size})`);
  });
});
console.log('WebSocket Server listening on ws://localhost:3001');
 
process.on('SIGTERM', () => {
  console.log('SIGTERM');
  handler.broadcastReconnectNotification();
  wss.close();
});

server/wsServer.ts
ts
import { applyWSSHandler } from '@trpc/server/adapters/ws';
import { WebSocketServer } from 'ws';
import { appRouter } from './routers/app';
import { createContext } from './trpc';
 
const wss = new WebSocketServer({
  port: 3001,
});
const handler = applyWSSHandler({
  wss,
  router: appRouter,
  createContext,
  // Enable heartbeat messages to keep connection open (disabled by default)
  keepAlive: {
    enabled: true,
    // server ping message interval in milliseconds
    pingMs: 30000,
    // connection is terminated if pong message is not received in this many milliseconds
    pongWaitMs: 5000,
  },
});
 
wss.on('connection', (ws) => {
  console.log(`++ Connection (${wss.clients.size})`);
  ws.once('close', () => {
    console.log(`-- Connection (${wss.clients.size})`);
  });
});
console.log('WebSocket Server listening on ws://localhost:3001');
 
process.on('SIGTERM', () => {
  console.log('SIGTERM');
  handler.broadcastReconnectNotification();
  wss.close();
});

设置 TRPCClient 使用 WebSockets

技巧

您可以使用链接将查询和/或变更路由到 HTTP 传输，而订阅通过 WebSockets 传输。

client.ts
tsx
import { createTRPCClient, createWSClient, wsLink } from '@trpc/client';
import type { AppRouter } from './server';
 
// create persistent WebSocket connection
const wsClient = createWSClient({
  url: `ws://localhost:3001`,
});
 
// configure TRPCClient to use WebSockets transport
const client = createTRPCClient<AppRouter>({
  links: [
    wsLink({
      client: wsClient,
    }),
  ],
});

client.ts
tsx
import { createTRPCClient, createWSClient, wsLink } from '@trpc/client';
import type { AppRouter } from './server';
 
// create persistent WebSocket connection
const wsClient = createWSClient({
  url: `ws://localhost:3001`,
});
 
// configure TRPCClient to use WebSockets transport
const client = createTRPCClient<AppRouter>({
  links: [
    wsLink({
      client: wsClient,
    }),
  ],
});

认证/连接参数

技巧

如果是 Web 应用程序，可忽略本节内容，因为 cookies 会随请求自动发送。

要在 WebSockets 中进行身份认证，您可为 createWSClient 定义 connectionParams。该参数将在客户端建立 WebSocket 连接时作为第一条消息发送。

server/context.ts
ts
import type { CreateWSSContextFnOptions } from '@trpc/server/adapters/ws';
 
export const createContext = async (opts: CreateWSSContextFnOptions) => {
  const token = opts.info.connectionParams?.token;
         
const token: string | undefined
 
  // [... authenticate]
 
  return {};
};
 
export type Context = Awaited<ReturnType<typeof createContext>>;

server/context.ts
ts
import type { CreateWSSContextFnOptions } from '@trpc/server/adapters/ws';
 
export const createContext = async (opts: CreateWSSContextFnOptions) => {
  const token = opts.info.connectionParams?.token;
         
const token: string | undefined
 
  // [... authenticate]
 
  return {};
};
 
export type Context = Awaited<ReturnType<typeof createContext>>;

client/trpc.ts
ts
import { createTRPCClient, createWSClient, wsLink } from '@trpc/client';
import type { AppRouter } from './server';
import superjson from 'superjson';
 
const wsClient = createWSClient({
  url: `ws://localhost:3000`,
 
  connectionParams: async () => {
    return {
      token: 'supersecret',
    };
  },
});
export const trpc = createTRPCClient<AppRouter>({
  links: [wsLink({ client: wsClient, transformer: superjson })],
});

client/trpc.ts
ts
import { createTRPCClient, createWSClient, wsLink } from '@trpc/client';
import type { AppRouter } from './server';
import superjson from 'superjson';
 
const wsClient = createWSClient({
  url: `ws://localhost:3000`,
 
  connectionParams: async () => {
    return {
      token: 'supersecret',
    };
  },
});
export const trpc = createTRPCClient<AppRouter>({
  links: [wsLink({ client: wsClient, transformer: superjson })],
});

使用 tracked() 自动追踪 ID（推荐）

若您使用 tracked() 辅助函数 yield 事件并包含 id，客户端在断开连接后将自动重连，并在重连时通过 lastEventId 参数发送最后已知的 ID。

初始化订阅时可发送初始 lastEventId，浏览器在接收数据时会自动更新该值。

信息

若基于 lastEventId 获取数据且事件完整性至关重要，建议使用 ReadableStream 或类似模式作为中间层（如 全栈 SSE 示例 所示），避免在基于 lastEventId 批量生成时忽略新产生的事件。

ts
import EventEmitter, { on } from 'events';
import { initTRPC, tracked } from '@trpc/server';
import { z } from 'zod';
 
type Post = { id: string; title: string };
 
const t = initTRPC.create();
const publicProcedure = t.procedure;
const router = t.router;
 
const ee = new EventEmitter();
 
export const subRouter = router({
  onPostAdd: publicProcedure
    .input(
      z
        .object({
          // lastEventId is the last event id that the client has received
          // On the first call, it will be whatever was passed in the initial setup
          // If the client reconnects, it will be the last event id that the client received
          lastEventId: z.string().nullish(),
        })
        .optional(),
    )
    .subscription(async function* (opts) {
      if (opts.input?.lastEventId) {
        // [...] get the posts since the last event id and yield them
      }
      // listen for new events
      for await (const [data] of on(ee, 'add', {
        // Passing the AbortSignal from the request automatically cancels the event emitter when the subscription is aborted
        signal: opts.signal,
      })) {
        const post = data as Post;
        // tracking the post id ensures the client can reconnect at any time and get the latest events since this id
        yield tracked(post.id, post);
      }
    }),
});

ts
import EventEmitter, { on } from 'events';
import { initTRPC, tracked } from '@trpc/server';
import { z } from 'zod';
 
type Post = { id: string; title: string };
 
const t = initTRPC.create();
const publicProcedure = t.procedure;
const router = t.router;
 
const ee = new EventEmitter();
 
export const subRouter = router({
  onPostAdd: publicProcedure
    .input(
      z
        .object({
          // lastEventId is the last event id that the client has received
          // On the first call, it will be whatever was passed in the initial setup
          // If the client reconnects, it will be the last event id that the client received
          lastEventId: z.string().nullish(),
        })
        .optional(),
    )
    .subscription(async function* (opts) {
      if (opts.input?.lastEventId) {
        // [...] get the posts since the last event id and yield them
      }
      // listen for new events
      for await (const [data] of on(ee, 'add', {
        // Passing the AbortSignal from the request automatically cancels the event emitter when the subscription is aborted
        signal: opts.signal,
      })) {
        const post = data as Post;
        // tracking the post id ensures the client can reconnect at any time and get the latest events since this id
        yield tracked(post.id, post);
      }
    }),
});

WebSockets RPC 规范

您可以通过深入查看 TypeScript 类型定义获取更多细节：

• /packages/server/src/unstable-core-do-not-import/rpc/envelopes.ts
• /packages/server/src/unstable-core-do-not-import/rpc/codes.ts

query / mutation

请求

ts
interface RequestMessage {
  id: number | string;
  jsonrpc?: '2.0';
  method: 'query' | 'mutation';
  params: {
    path: string;
    input?: unknown; // <-- pass input of procedure, serialized by transformer
  };
}

ts
interface RequestMessage {
  id: number | string;
  jsonrpc?: '2.0';
  method: 'query' | 'mutation';
  params: {
    path: string;
    input?: unknown; // <-- pass input of procedure, serialized by transformer
  };
}

响应

... 如下，或错误

ts
interface ResponseMessage {
  id: number | string;
  jsonrpc?: '2.0';
  result: {
    type: 'data'; // always 'data' for mutation / queries
    data: TOutput; // output from procedure
  };
}

ts
interface ResponseMessage {
  id: number | string;
  jsonrpc?: '2.0';
  result: {
    type: 'data'; // always 'data' for mutation / queries
    data: TOutput; // output from procedure
  };
}

subscription / subscription.stop

开始订阅

ts
interface SubscriptionRequest {
  id: number | string;
  jsonrpc?: '2.0';
  method: 'subscription';
  params: {
    path: string;
    input?: unknown; // <-- pass input of procedure, serialized by transformer
  };
}

ts
interface SubscriptionRequest {
  id: number | string;
  jsonrpc?: '2.0';
  method: 'subscription';
  params: {
    path: string;
    input?: unknown; // <-- pass input of procedure, serialized by transformer
  };
}

取消订阅需调用 subscription.stop

ts
interface SubscriptionStopRequest {
  id: number | string; // <-- id of your created subscription
  jsonrpc?: '2.0';
  method: 'subscription.stop';
}

ts
interface SubscriptionStopRequest {
  id: number | string; // <-- id of your created subscription
  jsonrpc?: '2.0';
  method: 'subscription.stop';
}

订阅响应结构

... 如下，或错误

ts
interface SubscriptionResponse {
  id: number | string;
  jsonrpc?: '2.0';
  result:
    | {
        type: 'data';
        data: TData; // subscription emitted data
      }
    | {
        type: 'started'; // subscription started
      }
    | {
        type: 'stopped'; // subscription stopped
      };
}

ts
interface SubscriptionResponse {
  id: number | string;
  jsonrpc?: '2.0';
  result:
    | {
        type: 'data';
        data: TData; // subscription emitted data
      }
    | {
        type: 'started'; // subscription started
      }
    | {
        type: 'stopped'; // subscription stopped
      };
}

连接参数

若连接通过 ?connectionParams=1 初始化，首条消息必须是连接参数。

ts
interface ConnectionParamsMessage {
  data: Record<string, string> | null;
  method: 'connectionParams';
}

ts
interface ConnectionParamsMessage {
  data: Record<string, string> | null;
  method: 'connectionParams';
}

错误处理

参见 https://www.jsonrpc.org/specification#error_object 或 错误格式化。

服务端到客户端的通知

{ id: null, type: 'reconnect' }

通知客户端在关闭服务器前重新连接。通过 wssHandler.broadcastReconnectNotification() 调用。